4 



£ s. d. 



Nachet's Prism for oblique light, with accurate revolving 



fitting 1 1 



Right angle Prism for reflecting the light more perfectly than 

 the mirror, with adjustments and fittings to the tri- 

 angular mirror stem complete, and the reflecting 

 surface uncovered for the convenience of wiping .. . 2 10 



Polarizing Apparatus, of two Nicol's prisms and one selenite 



film, with revolving fittings to all 2 10 



Barker's Series of Selenites, which give 13 difi'erent colours 

 and their complementary tints, mounted on an im- 

 proved plan for their more accurate and easy ap- 

 phance 3 10 



Barker's Series of Selenites, adapted to the Selenite fitting 



mentioned in " Polarizing Apparatus " 17 6 



Bundle of Thin Glass for polarizing by reflection or trans- 

 mission 110 



Black Glass for polarizing 15 



Dark Wells of three sizes, and holder 12 6 



APPARATUS 



AS APPLIED TO No. 3, No. 4 and No. 5 Microscopes. 



Achromatic Condenser of two powers, 60° and 20° of aperture, 



rackwork and complete adjustments to brasswork.. 3 

 Achromatic Condenser as above, with sliding fitting, and no 



adjustments to brasswork 2 5 



Achromatic Condenser, Lenses of 1 10 



Wenham's Parabolic Reflector, with sliding stop, rackwork, 



and complete adjustments to brasswork 3 17 6 



Wenham's Parabolic Reflector, with plain sliding fittings ... 2 10 



Nachet's Prism for oblique light 18 



Polarizing Apparatus, of two Nicol's prisms with revolving 



fittings, and one selenite film 2 10 



Dark Wells of three sizes, and holder 12 6 



APPARATUS 



for Microscopes in general. 



Extra Eye-piece for No. 1 Microscope 17 6 



Extra Eye-piece for No. 2, 3, 4, or 5 Microscope 15 



Extra Eye-piece for Hospital Microscope 13 



Indicator to Eye-piece 5 



Micrometer, with Jackson's adjusting screw and fittings to 



Eye-piece 10 



Micrometer for Stage, divided into lOOths and lOOOths of an 



iuch, and mounted in brass 10 



Micrometer for Stage, divided into lOOthsand lOOOthsof an 



inch, unmounted 5 



